Behavior
Primarily a nocturnal migrant. Diurnal onward migration occurs in spring in the
Gulf coast region and presumably in the far northern latitudes. Rarely seen in redetermined migration,
as this behavior apparently occurs to some degree prior to sunrise,
coinciding with a characteristic early-dawn period of increased nocturnal flight
call activity. Flight calls are given in
nocturnal migration and also in diurnal onward migration. Perched birds may give
flight calls at any time during the day, but they do so particularly
around dawn and dusk.